diff --git a/lib/youplot.rb b/lib/youplot.rb
index d7bcd80..9e8e6b0 100644
--- a/lib/youplot.rb
+++ b/lib/youplot.rb
@@ -3,6 +3,7 @@
 require 'unicode_plot'
 require 'youplot/version'
 require 'youplot/dsv'
+require 'youplot/parameters'
 require 'youplot/command'
 
 module YouPlot
diff --git a/lib/youplot/command/parser.rb b/lib/youplot/command/parser.rb
index 0a50e9c..7c128cb 100644
--- a/lib/youplot/command/parser.rb
+++ b/lib/youplot/command/parser.rb
@@ -2,7 +2,6 @@
 
 require 'optparse'
 require_relative 'options'
-require_relative 'plot_params'
 
 module YouPlot
   class Command
@@ -28,7 +27,7 @@ module YouPlot
           debug: false
         )
 
-        @params = PlotParams.new
+        @params = Parameters.new
       end
 
       def create_default_parser
diff --git a/lib/youplot/command/plot_params.rb b/lib/youplot/command/plot_params.rb
deleted file mode 100644
index 2f85592..0000000
--- a/lib/youplot/command/plot_params.rb
+++ /dev/null
@@ -1,37 +0,0 @@
-# frozen_string_literal: true
-
-module YouPlot
-  class Command
-    # UnicodePlot parameters.
-    # * Normally in a Ruby program, you might use hash for the parameter object.
-    # * Here, I use Struct for 2 safety reason.
-    # * The keys are static in Struct.
-    # * Struct does not conflict with keyword arguments. Hash dose.
-    PlotParams = Struct.new(
-      # Sort me!
-      :title,
-      :width,
-      :height,
-      :border,
-      :margin,
-      :padding,
-      :color,
-      :xlabel,
-      :ylabel,
-      :labels,
-      :symbol,
-      :xscale,
-      :nbins,
-      :closed,
-      :canvas,
-      :xlim,
-      :ylim,
-      :grid,
-      :name
-    ) do
-      def to_hc
-        to_h.compact
-      end
-    end
-  end
-end
diff --git a/lib/youplot/parameters.rb b/lib/youplot/parameters.rb
new file mode 100644
index 0000000..4c35b4b
--- /dev/null
+++ b/lib/youplot/parameters.rb
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+module YouPlot
+  # UnicodePlot parameters.
+  # * Normally in a Ruby program, you might use hash for the parameter object.
+  # * Here, I use Struct for 2 safety reason.
+  # * The keys are static in Struct.
+  # * Struct does not conflict with keyword arguments. Hash dose.
+  Parameters = Struct.new(
+    # Sort me!
+    :title,
+    :width,
+    :height,
+    :border,
+    :margin,
+    :padding,
+    :color,
+    :xlabel,
+    :ylabel,
+    :labels,
+    :symbol,
+    :xscale,
+    :nbins,
+    :closed,
+    :canvas,
+    :xlim,
+    :ylim,
+    :grid,
+    :name
+  ) do
+    def to_hc
+      to_h.compact
+    end
+  end
+end